An axle-shaft or half-shaft, is a mechanical component used for transmitting rotation and torque from a powerplant in a drive-train of a vehicle. Axle-shafts are typically used to connect a vehicle differential to driven wheels. Loads on an axle-shaft are mainly the result of engine output torque overlaid with the engine's torsional vibrations, and the vehicle's inertia. Axle-shafts are generally constructed to withstand operating stresses, while limiting additional weight and inertia. Vehicle axle-shafts frequently incorporate one or more mechanical joints designed to permit variation in alignment and/or distance between the driving and driven components.